Cystic Fibrosis (CF) is a lethal genetic disease characterized in part by one or more mutations in the cystic fibrosis transmembrane conductance regulator (CFTR). Mutations of the CFTR protein, typically a deletion of a phenylalanine at position 508 (deltaF508), disable the chloride ion transport activity of CFTR, leading to CF disease symptoms, especially in the lung epithelium. Relying on pharmacological techniques, this Phase I proposal characterizes membrane receptors and ion channels on selected epithelial cell lines that also express wild type or mutant (defective) forms of CFTR. The study will provide a composite of radioligand binding profiles (establishing the presence of various targets) and cellular response profiles of three different cell lines, CFPAC-1, PANC-1 and Calu-3. The cellular response will be measured as changes in intracellular Ca++ or cAMP concentration and in Cl- efflux when the cells are stimulated by receptor/ion channel agonists. The proposed body of research seeks to establish a system comprised of a set of targets, for instance a set (n is equal to or more than 2) of membrane receptors, which on agonist stimulation will mediate a potentially synergistic effect of enhancing Cl- secretion by the cells. This effect may occur either through stimulation of CFTR itself or, as a more novel approach, via stimulation of other Cl- transport mechanisms present in the cells. As a potential means to establish alternative targets and alternative therapeutic approaches for restoring Cl- efflux, this Phase I research should provide a significant contribution to cystic fibrosis medication development; as well as relevant information for related diseases in respiratory, urinary, reproductive, digestive and/or cardiovascular systems.